The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 06, 2001
Filed:
Nov. 03, 1999
Po-Cheng Kuo, Taipei, TW;
Chih-Ming Kuo, Taipei, TW;
Abstract
A method of producing high coercivity FePt—Si,N,granular composite thin films for magnetic recording media is invented. The method includes magnetron co-sputtering of FePt and Si,N,targets at controlled sputtering power and sputtering argon gas pressure to form a selective composition of granular FePt—Si,N,thin film on a low temperature substrate, then post-annealed in vacuum at selective time period and temperature. Two kinds of FePt targets can be used. One is the FePt alloy target. The other one is a composite target consisting of an iron disk overlaid with small Pt pieces. This arrangement provides a wide range of effective target compositions and therefore film compositions. FePt—Si,N,films were deposited on natural oxidized silicon wafer or quartz glass substrate at room temperature. The as-deposited film has soft magnetic properties and granular structure with soft magnetic &ggr;-FePt particles dispersed in amorphous Si,N,matrix. The as-deposited film cannot be used as magnetic recording medium due to its low coercivity. After annealing at controlled conditions for a desirable temperature and time period in vacuum, the film also has granular structure but the magnetic soft &ggr;-FePt phase is transformed into magnetic hard &ggr;,-FePt phase. This film has high coercivity and its magnetic easy-axis is parallel to the film plane. It may be used as high-density magnetic recording medium.